This page shows some equipment that was used during or after WWII to
find clandestine radio stations and intercept enemy radio traffic.
Much of this equipment uses
Morse Code
for the transmission of data.
Click any of the images below for a full description of each device.
Please note that the list is by no means complete. If you have any
further information to offer, or better: if you have any surplus
equipment available for the Crypto Museum collection,
please contact us.

Also note that the title 'Intercept equipment' doesn't fully cover
the nature of this section,
but we just couldn't find a better one. This chapter includes
equipment to locate clandestine radio stations, intercept spy
communication (spy sets and
surveillance radios) and find
listening devices (bugs).
A common name for the latter is TSCM (Technical Surveillance
Counter-Measures) [1].

This small receiver was used during WWII to locate clandestine
transmitters, mainly operated by German agents in and around London.
The unit is housed in a Bakelite enclosure and its lid acts as the
frequency range 'plug-in' as well as the direction-sensitive antenna.

The receiver is commonly known as the GPO-receiver, but its official
name was Tester WL-53400. It was only built in small quantities.

The Gürtelpeiler was probably the first body-worn intercept receiver.
It was used during WWII by the German secret services to locate
clandestine transmitters operating in countries occupied by the Germans.

The valve-based receiver can be concealed under the operator's clothing
with a loop antenna around the neck.

The AR-88 was a valve-based shortwave general coverage communications receiver,
developed and built by the Radio Corporation of America (RCA) in the
early 1940s.

Although the receiver was initially intended as the successor
to the AR-77 amateur receiver, the outbreak of WWII made it evolve into
a professional high-end military-grade intercept receiver
for which cost was no object.

During the Cold War, the USSR (Russia) developed a series of highly portable
intercept receivers that were deployed in most Warsaw Pact countries.
Such receivers where generally carried around the operator's waist, hidden
under his clothing.

They also developed stationary and mobile intercept radios and other
direction finding equipment.

This German-built portable direction finding receiver was used
in the Netherlands in the early 60s to track down clandestine
radio stations and foreign secret agents. The receiver is housed
in a wooden case, so that the internal window-antenna can be
used. It is operated by a trigger-switch hidden under the carrying
handle.

The PE-484 was a body-wearable miniature direction finder (Kleinstpeilemfänger)
introduced around 1958 by Telefunken in Germany.
It could be hidden inconspicuously under the operator's clothing
and was intended for tracking down clandestine radio stations.
In some countries, the PE-484 was used until the early 1980s.

This is a rare short-wave direction finder built in Chechoslowakia
around 1948.
It comes with four plug-in modules that can be inserted at the bottom
of the unit. Each plug-in unit covers a specific frequency range.

It was used by the Czech Secret Police to track down clandestine (spy)
radio stations during the Cold War.

This small hand-held direction finder that covers 3 to 145 MHz,
was built by the Austrian Radio Monitoring Service of the ÖPT in 1963,
especially for unobtrusively searching for clandestine radio stations,
such as Cold War spy transmitters.

The receiver is fully transistorized and comes with 15 frequency plug-in
units, nicely packed in a sturdy metal carrying case.

Micro-Tel
was an electronics company based in Hunt Valley
(Baltimore, US), specialized in developing an building
precision surveillance receivers for the US Goverment,
the Department of Defense (DoD), and various other agencies.

Starting in the 1960s, the company built a wide range of high-end
surveillance receivers and complementary equipment. Today, they are
known as Cobham Defense Electronics SIGINT.

Scanlock is a series of automatic bug-tracing receivers,
developed and marketed by Audiotel in the UK.
Audiotel have been developing and
manufacturing TSCM equipment since the late 1970s
and they are still in business today.

COMPUSCAN was an add-on to the
Scanlock Mark VB bug tracer
(shown above). It allowed a target area to be compared to
a safe zone several miles away. Any differences were then
identified as possible suspected signals.

Research Electronics International (REI) is a US manufacturer of
a wide range of TSCM equipment, ranging from simplug bug detectors
to fully computer controlled correlation receivers and spectrum
analyzers.

The American company OAR built a wide range of radio direction finders
that were intended as a navigational aid aboard ships. Special versions,
the so-called 9xx-range, were made for locating clandestine radio stations
(pirates).

The image on the right shows the ADF-940 which has a built-in 40-channel
scanner for the 27 MHz citizens band (CB).

Kolibrie (hummingbird) was a car phone intercept receiver
developed by the Police Signals Service in The Netherlands
in the early 1990s. It was intended for intercepting
criminal conversations on the early analogue car phone networks.

In the 1980s and 1990s, Schlumberger GmbH developed a series of
high performance digital programmable precision receivers,
under the name Minilock. The receivers were used by many agencies
for intercepting, measuring and fingerprinting radio signals.

The EB-100 is a small portable surveillance receiver build in the 1980s by
Rohde & Schwarz in Munich (Germany).
It was intended for a variety of jobs, including frequency monitoring,
radio surveillance, radio intercept, EMC measurements and direction finding.

Due to its small size and wide frequency range, it is extremely useful for
bug tracing. EB-100 is also known as MINIPORT.

The FSH-3 is a portable spectrum analyzer developed by
Rohde & Schwarz
in Munich (Germany).
It covers all frequencies between 100 kHz and 3 GHz and
is suitable for HF measurements as well as for bug tracing.

Delta-V is a small hand-held differential RF detector that allows easy
bug detection in a room, in a car or on a person, without in-depth
knownledge and expertise. The device is powered by an internal 9V battery.

Although the first version of Delta-V dates back to 1989, it has been
updated and enhanced several times since, and is still available from
the manufacturer today (2013).

The TCM-03 was a device for detecting bugs on the mains power cables
and on the (analogue) telephone lines. It was introduced in 1989
and was succeeded by the TCM-03 Mark II in 1992.
The TCM-03 was sold until 2013.

Osobnjak was a range of high-end counter­measures receivers,
developed by the Soviets for protection against
resonant cavity microphones,
a special kind of passive covert listening devices (bugs) that were
activated by a strong RF signal.

As the Soviets were the first to employ resonant cavity microphones,
they knew that sooner or later their Western counterparts would use
the same technology against them.